<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>变量</title>
</head>
<body>
    <script>
        var name = '张三'
        var age = 18
        console.log(name)
        document.write(age)
        // 修改变量
        name = '李四'
        //声明变量
        var addr
        document.write(addr) //undefined
        // 声明多个变量 
        var b1=1, b2=2, b3=3, b4
        document.write(b1,b2,b3,b4)
        var c1=c2=c3=100
        console.log(c1,c2,c3)

    </script>
    
</body>
</html>